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J. MoGULLOOI-I. BOOK DRILL.

No. 398,637. Patented Feb. 26, 1889.

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J. MGGULLOGH.

ROCK DRILL.

No. 398,637. Patented Feb. 26', 1889.

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ROCK DRILL.

No. 398,637. Patented Feb. 26,1889.

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ROCK DRILL. No. 398,637. Patented Feb. 26, 1889.

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ROGK DRILL. No. 398,637. Patented Feb. 26, 1889.

N, PETERS. Phcio-Lilhog apher, Washmgicn. D.C.

UNTTE STATES PATENT OFFICE.

JAMES MCCULLOCH, OF. MANCHESTER, ENGLAND.

ROCK- DRILL.

SPECIFICATION forming part of Letters Patent No. 398,637, dated February26, 1889.

Application filed June 29, 1888. Serial No. 278,602. (No model.)Patented in England August 16, 1887, No. 11,192.

1' 0 all whom it 7771M](HUME/ft! Be it known that 1, JAMES MoCULLocH,engineer, a subject of the Queen of Great Britain, and a resident ofManchester, England, have invented new and useful Improvements inRock-Drills, (for which I have obtained a patent in Great Britain, No.11,192, bearing date August 16, 1887,) of which the following is aspecification, reference being had to the accompanying drawings.

My invention relates to valves and valvegear chiefly designed forrock-drills.

The dist-ributingvalvcs of rock-drills have in some instances beenoperated by means of a tappet actuated by the piston or piston-rod inits to-and-fro movement. In such cases, however, it has been necessaryto use a spring for retaining the valve in position at either extremityof its stroke or movement while not acted upon by the piston orpiston-rod, and considerable inconvenience has been occasioned by thefailure of the said spring to properly fulfill its function by reason ofdiminution of its strength or by the friction caused by excessivetightening of the said spring. In other instances the valves ofrock-drills have been arranged to be operated by airpressure. Thisarrangement is unreliable, as the valve is apt to flutter or stick or berendered inoperative by the entrance of sand, grit, or the like betweenthe working-surfaces, the air-pressure then being insufiicient toovercome the increased resistance to movement of the valve. The springs,moreover, offer great resistance to the movement of the piston and causeconsiderable wear of the working parts, and when these parts areslightly worn the apparatus will not work properly (the valve not beingkept in its f proper place) until the springs are renewed or read usted.

when working underground. In the valveless machine, moreover, the motivefluid is in constant communication with the piston, thereby causinggreat resistance to the movement of the piston and waste of the fluid.

By my invention I obviate the above-mentioned defects and provide foroperating a distributirig-valve in an eificient and reliable manner bythe combined action of a tappet or similar device and of iiuitln-essure.

A great amount of trouble 3 and inconvenience is thus caused, especially5 My said invention comprises, moreover, other improvements, hereinafterset forth.

In the accompanying drawings I have shown how my said invention can beconveniently and advantageously carried into practice.

Figure 1 is a side elevation showing the application of my saidinvention to a rock-drill. Fig. ,2 is a plan. Fig. 3 is a longitudinalvertical central section. Fig. is a vertical section on the line a w,Fig. Fig. 5 is a vert-i cal section on the line 9; .r, Fig. 3. Fig. 6 isa vertical section on the line 1 y, Fig. 3. Fig. 7 is a vertical sectionon the line y y, Fig. 3. Fig. 8 is a plan,.and Fig. 9 a section on theline 2 2, Fig. 8, showing a modification hereinafter described. Fig. 10is a plan; and Fig. 11 is a section on the line .2 .2", Fig. 10, showinga further modification.

Like letters indicate corresponding parts throughout the drawings.

A is the cylinder.

B B are the cvlinder-covers.

C C are the pistons.

D is the pistoirrod.

E is the stop-cock, and F the supply-pipe.

G is the socket for holding the drill H.

I is the bracket carrying the cylinder.

J-is a handle for feeding the drill to or from its work by means of ascrew hereinafter referred to.

CL is a valve adapted to be moved by a tappet, b, which is pivoted at bto the cylinder A, and is actuated by a swelling or enlargement, 0, uponthe piston-rod D. The air or other fluid delivered through thesupply-pipe F and stop-cock E is caused by the tappet valve a to passalternately through the two channels or passages ct to the extremitiesof the cylinder A and expands in the said eylinder. Holes (Z (I areformed in the cylinder A, through which the exhaust wili take place. Asthe piston C passes theupertures d d, the 1 compressed air or othermotive fluid behind the piston exhausts through said apertures until theair behind said piston is in a state of equilibrium with the atmosphericair.

Upon the return-stroke of said piston the air piston will be compressedbetween the piston and cylinder-head. The air thus compressed provides asafe cushion at each end of the i said stroke and prevents damage to thecovers 1 thus remainlng 1n the cylinder behind the l B B by the pistonsC C. The air compressed, as above described, expands in the returnstrokeof the pistons C C, and thereby augments the power or initial pressuretending to move the said pistons. Vhen the pistons O C are performingtheir forward stroke or niovenient thatis to say, the stroke in whichthey deliver the cutting-blow of the drill l-I- resistance due to theabove-described cushioning does not offer any appreciable opposition tothe force of the cutting-blow of the drill except when the pistonstravel too far-as, for instance, when the said drill comes in contactwith soft places in the rock, or when the apparatus is not keptinp toits proper working position. The atmospheric air is prevented fromentering the channels or passages a, through which the moti ve fluid isdelivered to-the cylinder A, by valves 6, provided with seatings f. Thevalves 6 are normally retained closed by springs g. When the atmosphericair is being compressed, as hereinbefore described, in either end Of llIQ cylinder, the pressure of the said air tends to press the valve 6 inthat end of the cylinder A tighter upon its seating f, while the valve 6in the other end of the said cylinder is opened by the air or otherfluid delivered by the tappetvalve a through the passage a, the pressureof the said air or other fluid being sufficient.

to overcome the strength of the spring g. This action takes placealternately at either end of the cylinder.

An important feature of my said invention is the construction andarrangement of the distributing-valve and its adjuncts in such a mannerthat when the said valve is moved to one end of its stroke to close oneof the said ports and open the other port the pressure of the compressedair or other fluid acting upon the said valve will retain the same inposition, and thus prevent movement thereof while the projection orenlargement c of the piston-rod D is out of contact with the tappet b.For this purpose I make the said valve as shown and fit it toslide in acylinder or casing, provided with an oil-hole, a The said valve isprovided with recesses or cavities a in which works the extremity o ofthe tappet b. I moreover provide steel disks a having india-rubber disksa in the center. Against these steel disks the surface of one or theother end of the valve a will be pressed by the tappet b at eitherextremity of its movement. \Vhen desired, the valve a can be reversedand the extremity b of the tappet I) inserted in the other recess orcavity, (t hen at either extremity of its movement the valve a closesthe port through which the compressed air has access to it, so that thesaid end of the valve is no longer subjected to the pressure, and thecompressed air acting upon the remaining surfaces of the valvewill tendto keep it pressedagainst the said disk.

To impart rotary or angular motion to the drill H upon or about its axisat the same time that it delivers its cutting-blow, a spindle, h,

is fitted in the cylinder-cover l3. The spindle h is provided withspiral grooves h, in which are adapted to fit correspondingfeathers orprojections upon a bush, 1, fitted in the piston O, which is recessed orhollowed out. for that purpose. A hole or cavity, j, is also provided inthe piston-rod D to receive the spindle h durin the inward stroke of thepiston. The spindle h is moreoverprovided with a ratchet-wheel, k, withwhich engages pawls 71, actuated by springs 76 during the outward strokeof the pistons. \Vhen the drill H making its cutting-blow-that to say,when the pistons O O are making their outward stroke-the said pistons,the piston-rod D, an d the drill H are caused to rotate by the action ofthcgrooved spindle 71 upon the piston C. Upon the return-stroke thepawls It" do not engage with the ratchet-wheel k, and the latter, withthe spindle h, is free to revolve.

The cylinder A is provided with V-shaped projections land is arranged toslide in corresponding grooves, Z", in the bracket I. To feed the saidcylinder, and consequently the drill H, to or from its work, I provide ascrewthreaded spindle, m, carried in a suitable bearing, m, in thebracket I, and in a bear in g, 171*, in an extension, m of the saidbracket. The screw-threaded spindle m is arranged to engage withcorresponding threads in nuts 92, attached to the cylinder A. Thisspindle m is worked by means of the crank-handle J, as above stated. Totake up any wear that may take place in the screwthreads upon thespindle m or in the nuts 02, the latter are provided with right and lefthand screw-threads n upon the outside of the same. The nuts n are fittedwith'a nut, 0, having right'and left hand screw-threads adapted toengage with the external screw-threads upon the said nuts n. Thus byturning the nut 0 any wear can be taken up and the jar to which machinesof this kind are liable after a little wear is obviated. Nuts 1) areprovided for taking up the wear in the journal m Suitable packing, q, isprovided round the piston-rod D and grooved spindle h. Screwthreadedplugs r are provided, by removing which the tappet-valve a can be takenout for inspection or repair. A screw-threaded plug, 8, is also providedto permit access for oiling or inspecting the ratchet-wheel and thepawls I a.

Figs. 8 and 9 illustrate a modification wherein the cylinder A isarranged to slidein a bracket, 1, having at one side a V-shaped groove,1, in which is adapted to slide the corresponding V-shaped projection,Z, upon the said cylinder. The V-shaped projection upon the other sideof the cylinder .is adapted to slide in a recess, 2, provided with asetting-up strip, t. The strip 15' can be set up by means of set-screwsu when necessary, so as to take up any wear that may occur.

Figs. 10 and 11 illustrate a modification wherein the bracket I isprovided with a movable part or portion, 1', attached to the 1. In arock-drill or other machine, the com-' bination, with a piston and atappet operated by said piston, of the valve engaged with said tappetand having pockets in its ends forming chambers for receiving thepressure of motive force to hold it in position, substantially as shownand described.

In a rock-drill or other machine, the coml i11ation,with the cylinderand the doubleended piston, of the exhaust-ports (I, placed at adistance from the ends of said cylinder, and el1eck-valves in thesupply-passages for preventing the escape of the air in the ends of thecylinder, substantially as described.

3. In a rock-drill or other machine, the combination, with the cylinderA, bracket I, and screw-threaded spindle m, mounted in said bracket, ofsermvthreaded nuts 97-, mounted .on the cylinder and engaging with thespindie, and an auxiliary nut, o, placed around and screwed upon nuts11, for compensating for the wear'upon said nuts, substantially asdescribed.

I11 testimony whereof I have hereunto signed my name in the presence oftwo subscribing witnesses.

J. MCCULLOCH.

Witnesses:

I. SUTHERLAND MACKAY, CHARLES J. JAINEY.

